Epigenetics: The Beginning of Life on Earth and the Evolution of Human Beings

  • Publication date May 29, 2025

Lucia Tomas Grau

Introduction and Rationale

Students are creatures who absorb incredibly fast different contents, especially when they are younger. That is why we, as teachers, must keep them engaged by creating effective, dynamic, and challenging units. My unit is based on these approaches; thus, I consider my 4th grade students’ interests as well as their curious personality. In this way, they feel motivated and curious to deepen their knowledge, what is key to becoming successful in their learning.

My unit’s goal is to cause this willingness on my students in order to understand and assimilate better its contents. This curriculum unit will focus on how we evolve and develop from a single cell and what makes us different from chimps with almost the same DNA. Although explaining evolution and the meaning of cells and genes is not an easy task, my goal is that my students explore this topic through different resources such as visuals, videos, articles, books, and even microscopes to be able to understand why cells and genes are so important for life and the role they play in our bodies. They will discover the beginning of a human body formation which will lead to human evolution and development. Moreover, all the resources that I will provide plus their own research will allow them to examine the differences between us and chimpanzees, concluding how we ended up as humans if we were chimps before.

When I think about my students’ interests, I realize that most of them want to know more about the big questions of life: Where do we come from? What are our origins? How do we develop from a single cell? These are just some examples that make my students feel intrigued and motivated to explore and know more. When I had to decide my unit topic the first thing I thought about was my students. I have a large Spanish-speaking population in class. I have students from Mexico, Honduras, Guatemala, Cosa Rica, Venezuela…So the diversity is very present which means that I must transmit equity values. It does not matter where we come from, our race or, either our skin color, all of us come from one cell. That is why I ended up choosing the world of cells and DNA. “Each of us began life as a single cell,” says Ben Stanger. However, how can a cell become something as complex as a human being or an animal? If we think twice, it is incredible that any of us are here. According to the National Library of Medicine, life first emerged at least 3.8 billion years ago, approximately 750 million years after Earth was formed, but how the first cell was formed is still a matter of speculation. So, it makes us more curious as all of us want answers right away. The teaching and learning process will not be easy as my students will have to do research, read, explore and share knowledge, all of which build critical thinking. Despite this complex but also interesting and exciting topic, all my students will embark on a spectacular journey to discover our origins and development as humans.

This unit is designed to carry out with elementary students from 4th grade. They will be introduced to how life began by reading the book We Go Way Back by Ben-Barak and Philip Bunting. Through this book, they will discover how it is thought life started on the Earth and the first signs of life manifested by exploring the meaning of a cell.  As they build the basic knowledge, they will move on to explore the human cells, focusing on how they work and communicate to build a human body through their DNA, genes and proteins. Understanding these concepts will lead to analyzing how we evolved from our ancestors and how we differ from chimpanzees. My unit’s main goal is to answer at least some of their questions by approaching their interests and building knowledge about the evolution and development of humans.

My spirit as a teacher leads me to ensure that every student reaches successfully this unit’s goal. Thus, I will be my students’ model and guide, being part of their learning process by using active methodologies so my students are the focus of this process. How can students progress and succeed in their learning without a guide? Well, it can be that some of them get it, but not all of them. So, I have the responsibility to enrich their minds with knowledge and experiences besides letting them be curious and reaching the answers to their inquiries. I will walk with them and listen to their concerns and inquisitiveness, ensuring equity and a safe environment in order to learn in an efficient way.

Demographics

I teach at Skelly Elementary School, located in Tulsa, Oklahoma. It is a part of Tulsa Public Schools (TPS) and is one of the biggest elementary schools with more than 600 students enrolled. The school has two separated buildings, primary and upper, offering services from prekindergarten to 5th grade.  Both buildings count on all the necessary equipment to facilitate our teaching and the students’ learning. For instance, TPS provides the school with all the computers needed, so each student has a Chromebook to use in class. They will use it for carrying out research, watching videos and searching for some complementary information. Based on Niche.com data, the student population is made up of 50% female students and 50% male students. Also, it exists a racial and economic diversity what means I have students with diverse backgrounds. But mostly, the school enrolls 90% economically disadvantaged students what triggers pupils with low curricular level. Indeed, Niche.com shows that only 4% of the students scored at or above proficiency levels on their state reading assessment. In addition, it is a dual language school which offers program for native Spanish-speaking students to gain fluency and literacy in English and Spanish. For example, almost all my students come from Latin American countries having Spanish as their mother tongue. All of this triggers a challenge for teachers to develop an instructional methodology.

Pedagogical Philosophy

My experience of teaching for 7 years now, tells me that putting students as the subject of the teaching and learning process and letting them be an active part of it, triggers a much more efficient instruction and a satisfactory feeling. I have taught 4th, 5th and 6th grade the most of my years, focusing mainly on reading skills but also using innovative methodologies such as cooperative learning strategies, to engage my students in their learning. It implies creativity, hands-on activities and projects. It is precisely the way we will work in class to get the goals of this unit. My present room is composed of 18 students mostly from Latin American countries.

Thus, it exists a variety of levels in my class, from those who scored above proficiency levels to those who struggle in reading and writing. That is why my students are placed in groups of 3 or 4, being, at least, one of them with high level, so I try to balance the level of each group. This organization facilitates the use of cooperative techniques such as “Think, pair and share”. They can read all together, share opinions about what they read or watch, help each other, etc. All in all, they can enrich each other.

Unit content

How are we so different when we have similar DNA?This will be the main subject of our unit. The aim is that my students be able to understand why we have different traits and look different having similar DNA to others. They must explore and explain the answer to this mystery at the end of the unit. Thus, to reach the main issue I will provide the necessary content by answering the following riddles which, at the same time, cause curiosity in my students. We will focus on these three main questions:

  1. How do we develop from a single cell? What is a cell? What makes us special if we are all made up of the exact type of cells?
  2. What makes us different from chimps if we share 98.8% of DNA?
  3. The human body contains around 50-100 trillion cells, that all originate from just one, a fertilized egg, with the same DNA. How is it possible that all of them vary widely in size, number, structure, and use?

All these questions can be answered by a similar mechanism: the activation of genes. So, extremely similar genomes can still give rise to different organisms if the genes are activated at different times and strengths. But, before digging into the answers, my students need to understand the basic knowledge. They must know what a cell is, how it looks like and what a gene is and its replication.

Cells, genes and their functions

The cell is the basic unit of life for all organisms. Every organism has at least one cell (that is the definition of organism). To master this concept my students will launch their previous knowledge and then, they will connect this with the construction of the new learning by reading the book Cells: An Owner’s Handbook by Carolyn Fisher.

Although there are different kinds of cells like prokaryotes, considered to be single-cell bacteria and which were likely the first life on Earth, appearing about 3.5 billion years ago, we will focus on eukaryotes cells. Eukaryotes come in different forms, ranging from single-cell yeasts to large, complex and multicellular organisms, such as us. So, human cells that are classified within eukaryote cells, have internal compartments separated by membranes. The membranes enclose the two main parts of individual cells, nucleus and cytoplasm, between which various communications and activities happen. In humans, cells build tissues, tissues form organs, and organs work together to keep the body alive.1

Once my students get familiar with the concept of cell and its function, it is time to find its connection with our genes.

Within the nucleus of every human cell is the DNA (deoxyribonucleic acid) which contains the body’s genetic information and the chemical that makes up each chromosome. Also, inside of each chromosome, DNA molecules form codes (genes), that are templates for the production of proteins which have different functions and are the responsible to determine all physical traits and govern the function of all cells, tissues and organs. DNA sequences or genes are codes for proteins and the complete set of genes is a genome.2 There are other sequences of DNA that regulate the transcription of the gene.

One of the functions on DNA is to replicate within the nucleus, so it makes identical copies of itself. Replication is the production of continued cell, from the single-celled zygote to two cell, then four, and so on, to the fully formed body with all its tissues and organs.

For example, a single human zygote eventually results in more than 10 trillion cells, each one having the exact same DNA. So, the production of identical daughter cells from a parental cell involves one DNA replication followed by one cell division. This process is called mitosis. Also, there is another replication process called meiosis whose replication does not result in identical copies of the parent cell and the parent cell’s DNA as in mitosis. Meiosis involves one DNA replication followed by two cell divisions. It means that, during reproduction, each parent only contributes half of his or her genetic material. So, meiosis plays a critical role in the inheritance of biological characteristics and the variation seen in offspring.3

However, how do we tie all those questions together? I mean, how do we explain the pattern of variation and development with great genetic similarity?

The answer is epigenetics. According to Dr. Himabindu Sreenivasulu, epigenetics refers to the study of changes in gene activity that occur without altering the underlying DNA sequence. It’s like a layer of instructions that sits on top of your genetic code and influences how genes are turned on or off. As we said above, the activation of the genes can determine our physical traits.4

But what determines whether a gene’s switch is on or off?The decision is made by a class of proteins that we can think of as the executives: their job is to decide whether certain genes are to be on or off. They do this by recognizing and binding specific DNA sequences near particular genes and regulating their transcription into RNA. Hence their name: transcription factors.5

Genes are generally activated when a specific protein binds to their promoter, a short stretch of DNA just before the start of each gene; the protein then reads the DNA that constitutes the gene and makes an RNA “working copy” which is used by the cell. Cells can regulate the activity of a particular gene by controlling when and how these proteins bind to their promoter6.

Therefore, epigenetic modifications are a bit like ornaments on a Christmas tree; the tree (the DNA sequence) is still the same, but the decorations (epigenetic modifications) change how it’s perceived.

Two major kinds of epigenetic modifications are methylation, where a chemical group (a methyl) is attached to the DNA in specific locations, and histone modification, chemical modifications of a histone, a scaffolding protein in the nucleus which acts as a spool around which DNA is wound. Methylation usually reduces the activity of a gene, either by blocking proteins from binding to its promoter or by recruiting other proteins that wrap the DNA up and make it inactive. Histone modifications can affect how accessible a region of DNA is, making a gene more or less active. One way to understand how these modifications can alter gene expression without changing the DNA sequence is to think of the effect font has on text. Precisely the same letters arranged into the same series of words can have a different impact if the font emphasizes certain words. For instance, a gene’s activity, or expression, can be turned up or down like the volume on a radio.7

In a narrow sense, a cell is an autonomous living unit that acts as a decoding machine for a gene. Genes provide instructions to build proteins that perform virtually all the work in a cell. Proteins enable biological reactions, coordinate signals within the cell, form its structural elements, and turn genes on and off to regulate a cell’s identity, metabolism, growth and death. They are the functionaries in biology, the molecular machines that enable life.

Genes are located in a double-stranded, helical molecule called DNA (deoxyribonucleic acid), which is further packaged in chromosomes. As far as scientists know, DNA is present inside of each living cell. To simplify, a gene carries the code; a cell deciphers that code. A cell thus transforms information into form; genetic code into proteins. A gene without a cell is lifeless. What does a cell do with the proteins? A cell uses them to coordinate its functions, its behavior (movement, metabolism, signaling, delivering nutrients to other cells, surveying for foreign objects) to achieve the properties of life. For example, the reproduction of an organism begins and ends in the reproduction of a cell.

Besides, a cell, it is a dividing machine. Molecules within the cell -again, proteins- duplicate the genome, so the internal organization of the cell changes and the chromosomes divide. Cell division mainly drives growth, repair, regeneration and reproduction8 which we will talk about later.

Difference between humans and chimps

Figure 1. The phylogeny of living species most closely related to us9

Now that we know a little bit more about how cells and genes work, we go back to one of our issues. How are we different from chimps if we share 98.8% of DNA?

Before answering this question, it is important to remember that:

  • Humans did not evolve from chimpanzees. Humans and chimpanzees are evolutionary cousins and share a recent common ancestor that was neither chimpanzee nor human.
  • Humans are not “higher” or “more evolved” than other living lineages. Since our lineages split, humans and chimpanzees have each evolved traits unique to their own lineages.

This tree is based on morphological and genetic data. Chimpanzees and humans form a clade (they have a common ancestor) with DNA sequences that differ by only 1%. This genetic similarity made it hard to figure out exactly how these two primates are related, but recent genetic studies have strongly suggested that chimpanzees and humans are each other’s closest living relatives.10

How did humans evolve? About six million years ago in Africa, the chimpanzee lineage and our own split. What happened to us after that split? The hominid lineage did not march in a straight line to Homo sapiens. Instead, the early hominid lineage gave rise to many other (now extinct) hominids. Examining the fossils, the artifacts, and even the DNA of these relatives has helped us understand how this complex hominid tree evolved, and how modern humans came to exist.

Here are some of the important events in human history, with approximate dates, which reflect the evidence currently available:

Figure 2. Hominid tree evolution11.

Coming back to the main focus, if human and chimp DNA is 98.8 percent the same then why are we so different?  Numbers tell part of the story. Each human cell contains roughly three billion base pairs, or bits of information. Just 1.2 percent of that equals about 35 million differences. Some of these have a big impact, others don’t. And even two identical stretches of DNA (genes) can work differently–they can be “turned on” in different amounts, in different places or at different times.12

It means that although humans and chimps have many identical genes, they often use them in different ways. The differences between us and chimps do not come solely from differences in what genes we have, but also in how they’re regulated. Extremely similar genomes can still give rise to different organisms if the genes are activated at different times and strengths.13

So, the same gene can be turned up high in humans, but very low in chimps. For example, the same genes are expressed in the same brain regions in humans, chimps and gorillas, but in different amounts. Thousands of differences like these, affect brain development and function, and help explain why the human brain is larger and smarter.

Also, the chimpanzee immune system is surprisingly similar to ours. Most viruses that cause diseases like AIDS and hepatitis can infect chimpanzees too. But chimps don’t get infected by the malaria parasite Plasmodium falciparum, which a mosquito can transmit through its bite into human blood. A small DNA difference makes human red blood cells vulnerable to this parasite, while chimp blood cells are resistant.14

Another interesting example is hair. Chimps and humans have the same amount of hair follicles. So why aren’t humans covered in hair like other primates if we have the same number of hair follicles? Cutting your hair does not hurt because the hair on your scalp is not made up of live cell. But, under your skin, are the live cells of the hair follicle from which the hair grows. Living cells inside each hair follicle multiply and divide like many other body cells do. This process fills up the space inside the hair follicle and pushes older cells out of the hair shaft. Once outside the follicle, the cells die and harden. This is your hair, a bunch of dead cells and a protein called keratin15.

Thus, chimps’ hairs divide more and faster, so they are long and dark and human hair divides less. The explanation of that is that chimp’s hair genes switch on in a higher intensity than humans’ hair genes.

In conclusion, although research and experimental methods are developing, it is now generally accepted that both changes in gene regulation and alterations of protein coding sequences might have played a major role in shaping the phenotypic differences between humans and chimpanzees.

After having a better understanding of how genes work to produce those differences between us and chimps, it is time to dig into one of the questions my students are more interested in.How do we arise from a single cell and develop different traits?

From a cell to an embryo to a complete body

The human body contains around 50—100 trillion cells, that all originate from just one, a fertilized egg. They vary widely in size, number, structure, and use.

But, also, cells communicate with each other. Whether in plants, humans, or animals, they connect to create a solid, well-formed organism. Thus, how do the cells communicate to create a complete body?

The key is development, the process through which a single-celled egg gives rise to a complex, multi-billion-celled animal. In addition, development is intimately connected to evolution because it is through changes in embryos that changes in form arise.

Nevertheless, it all begins with fertilization, the fusion of two gametes -the sperm and egg- each carrying half of the DNA of the parent, into a single-celled zygote16. This fertilized egg is able to grow into 10 trillion cells that are formed into organs, tissues and other parts of the body.17

The replication or continued cell production, which we have already explained, is key to understanding how an organism shapes, forms and grows. That is when a cell divides, this makes a high-fidelity copy of its DNA, which then passes along to its daughters.18

However, how are the limbs, fingers and different shapes of our body formed? From the fertilized egg on, cells typically have somewhat different makeup in different regions, often including one side anchored to some connective tissue or its sides tightly stitched by particular attachment structures to adjacent cells, plus a side that is open to the environment and where most of the signal molecules are found on the cell’s surface. So how do asymmetries such as left and right, front and back, top and bottom sides arise?  First of all, to develop properly in the body, a cell needs to be in constant communication with its neighbors. It’s as if a unique protein in one section of the egg tells all the cells formed there, “You be a front cell, or You’re a back cell.” Then, as cell division progresses and more and more cells populate the embryo, they begin chattering chemically to each other, specifying more and more complicated information about shape, function, and position. A cell destined to form a foot, for example, might send a message to a neighboring cell directing its descendants to switch on genes that direct the cells outward and shape them into a leg. If a cell splits into two, one descendant cell can become the forerunner of the left and the other of the right side of the body. After the split, barrier molecules can be secreted by each cell that separates it from its neighbor, so that each divides into a separate, isolated “tree” or branching of descendant cells into separate structures as the embryo develops. Each descendant limb—cell lineage—in this branching pattern is then instructed by its progenitor to express particular genes, secrete particular signals, and so on, cell generation after cell generation.19 As cells divide, hierarchies of signaling can lead to differentiation, as for example first setting up a limb, then the divisions of the limb (upper and lower arm), then later structures (wrists and ankles, fingers and toes).  It is the local signal environment that directs the immediate structures, and that environment can change along an axis, as cells stop secreting one kind of signal (or stop producing receptors to enable them to detect it), and start producing other signals. Most organs or organ systems in animals—and plants, too—consist of many repeats of the same structure. Some signals called “activators” trigger receiving cells to undergo differentiation by expressing genes that generate, say, a hair follicle. Other signals are produced, called “inhibitors” that signal neighboring cells to shut down or not to activate those cascades. But a few cells away, the inhibitor signal weakens and the activator signal takes over, initiating the cascade to produce a new follicle. Repetitive patterning may involve many genes, but in principle it is a nested cascade of signaling that gets used repeatedly: you don’t need a separate gene for each hair or tooth. Repetitive patterning is a basic way in which animals and plants generate their different organs and structures and explains how they can become both so large and so complicated20.

According to Lewis, a geneticist at Caltech and one of the pioneers of the field, once you realize how much complexity there is in a single cell, the complicated body structure you see in higher organisms isn’t that surprising. “Each cell in a higher organism tends to be only a specialization of the basic cell that could originally do everything”, he says.  However, not all the developmental genes in your DNA legacy function all the time. Each gene has a switch that controls whether it is “on” or “off.” If the switch is in the “on” position the gene will spring into action; if the switch is in the “off” position the gene will remain at rest. But silent genes in your cells can be switched on; active ones can be shut off. Such genes, stimulated or deactivated, can produce or repress proteins that alter both the shape and the behavior of each cell. Turn on one combination from among your 100,000 genes and the cell will become a brain neuron; turn on another combination and it becomes a bone cell in your fingertip.21

These roughly 100,000 genes, with a potentially immense repertory of cell-building functions, are the real secret to a cell’s body-building talents.22

Teaching Strategies

The strategies used in this unit will foster my students’ motivation, participation and assimilation of the content through readings, discussions, visuals and sharing ideas. The investigation will be the focus of my students’ learning process. They will carry out research by looking up the key questions of the unit.

Think-Pair-Share

My students will use this strategy very often because the unit requires a lot of communication among the students. They must think about the meaning of the text or of an image or even the answer to a question. Then, they will share their ideas with their classmates. Undoubtedly, it helps to build comprehension and better relationships.

Partner Reading

The “Partner Reading” technique is used very often in my teaching. As my students have to read some texts along the unit, they will support each other by reading. In partners, they will name who is A and who is B so the letter that I indicate will start reading while B follows the text until it is their turn to read. It is a very enriching technique because they help each other to read better and to have a deeper understanding of the text.

Close Reading

This reading strategy will allow my students to understand better the texts. It requires students to slow down, think, annotate, and reflect. Apart from that, I will choose the appropriate texts to read in class considering their level and knowledge. For instance, we will use this strategy with the book called We Go Way Back by Ben-Barak and Philip Bunting, which the whole group will read in class. I will launch some questions before and during the reading to guide them in their comprehension and to focus on the important characteristics. Questions will facilitate the discussion between the students and get to the key insights.

Three Step Interviews

To engage students in their learning and understanding process, I will use “the three step interview” which is a cooperative learning strategy that encourages students to develop active listening skills by quizzing one another, sharing their thoughts, and taking notes.

For instance, I will divide my students into groups of three, and will assign them three roles: interviewer, interviewee, and notetaker. So, the interviewer will ask some questions related to the topic of discussion such as, how are the organs of an embryo formed?

They will be discussing the topic for 5 to 10 minutes to find the key information relating to the topic. Then, the students of each group will rotate roles to let the students strengthen their connection with the unit content in a creative and engaging way.

Classroom Activities

The plan for these activities is to follow them for three weeks approximately, starting by finding out what a cell is and how cells and genes work and make us different from each other with the exact type of cells. Students will then explore how we differ from chimps if we share 98.8% of DNA and finish the unit by studying the development of a human being from a single cell to a complete body.

Understanding Cells and Genes

To start with, my students will write down their prior knowledge about how life began. They will express their thoughts using the KWL technique (I Know-I Want-Learned) which ties together students’ prior knowledge, their desire to learn more, and the conclusions of their learning. My pupils will have a chart to fill out what they know about the beginning of life (it can be any ideas, examples that come up to their minds) and what they want to know about it. These first two steps will take place before reading texts and watching videos. The third step (what they have learned) will be completed after they have finished the next tasks.  

After a first approach, my students will watch a video to introduce how life began, called “The very first living thing.”23 While they watch the video, they will take notes in their notebook about the most interesting facts. Once they have finished it, students will walk to the charts that are hung on the wall to share and write some facts they learned on the video. Then, the different groups will share the information out loud.

Using the “Think-Pair-Share” strategy, my students will define what is a “cyanobacteria” and what is his role in the formation of first life beings. For that, they might go back to the video “The very first living thing” and watch the part where it is explained.

We will keep discussing how life arises by focusing on cells. For that, we will read the book The Universe In You using “close reading” strategies. This book explains the evolution from the first living thing to now.

To get a better vision of how life was formed on Earth and how humans evolved from a single cell, my pupils will watch a video called “Evolutionary History: The Timeline of Life.”24 They must take notes about it because students will ask questions to each other using “the three step interview” strategy. In this way, they will test if they have paid attention to the video. One of the students will be the interviewer, the other the interviewee who must answer the questions and the third one will be the notetaker who will take notes about the answers. Then, they will switch roles.

After having a wider knowledge about the origin of life, my students must put some pictures of life events in the correct order such as dinosaurs, asteroids exploding and volcanic eruptions, temperatures cooling down, molecules, prokaryotes cells, eukaryotes, etc. I will provide them with pictures of these events. They will develop this activity in pairs and may use the computer to search for some information to figure out the order of these life events. Thus, they will discover that life began with a single cell.  

After that, my students need to understand how a cell became a cell, I mean, which molecules came first to form a cell. For that, they will watch this video, “The RNA origin of life”25 and will walk through the different posters that are hung on the walls to write about and draw the contents that showed up in the video. There will be three posters: the DNA, the RNA and the proteins. Then, we will discuss as a whole group what they wrote and drew in the posters.

Now it is time to answer the mystery of diversity: “Why do we, humans, look different if we are all made up by the same cells?” They must research the answer by reading some articles such as “What Is Genetic Diversity and Why Does it Matter?”26 and watching some videoslike “Epigenetics”27 or “Gene Expression and Regulation.”28 After their research, they will walk towards the chart that displays the big question and will write and share their conclusions.

What makes us different from chimps having similar DNA

After having a basic knowledge about the role of genes in diversity, I will launch the following question to my students to start the second week: Why do we look so different to chimpanzees if we share 98.8% of DNA?  So, the students will start the second week exploring it. They will answer the object question using the “Think-Pair-Share” strategy. So, we will have the opportunity to discuss their different answers.

After that, in groups of four students, they will write over some charts about differences between chimpanzees and humans. Then, they will share them outloud. In this way, I know my students’ prior knowledge about chimpanzees.

Secondly, we will explore some photos of primates and their family tree. After that, I will provide them with some pictures of primates such as gorillas, chimpanzees, orangutans and humans so my students will put them in order in the family tree template. We will look over it and discuss that humans did not evolve from chimps, as is a frequent misconception. However, both share a recent common ancestor.

To get a better understanding of how we evolved, my students will watch the video “Human Evolution: We Didn’t Evolve From Chimps”29.

Once they know a little bit more about human evolution, it is time to dig in on the key question “How do we differ from chimps if we share 98.8% of DNA?” For that, we will start watching a video segment from The Human Spark30 thatlooks at four different experiments that make direct comparisons between the skills of young children and apes. The experiments cover a wide range of tasks which assess the ability to deal with the physical world of objects as well as social skills. The similarities between chimp and human behavior suggest that these skills were most likely a characteristic of our common ancestor. After watching the video, my students will discuss these two questions:

  1. Describe the four different experiments highlighted in the video.
  2. What were the similarities and differences between each experiment conducted with children and the corresponding chimp experiment?

However, what makes us different? My students will read an article called “Understanding our past: DNA”31 which compares chimps and humans and explains what makes our traits so different from chimps. We will use the “close reading” strategy and will discuss the answer to the previous question. Also, to complement the reading, we will watch a video called “How Humans Are Almost Identical to Chimps, According to DNA”.32

Besides that, my students will be able to do some research about this theme using some resources such as: National Geographic website, books and magazines from the school library and some apps that they have installed in their computers like “Pebble Go.”

Human Development from a Cell

Our third week will be designed to understand how we, human beings, develop from a single cell to a complete body.

We will start reading the book “We go way back”33 to ease into the beginning of life from a cell to all of us. We will use the “Close Reading” strategy to read the book as a whole group and to foster our understanding. While we are reading it, I will launch some questions to focus on the main ideas. Then, we will discuss what is a cell and I will provide some white paper to draw a cell and write some ideas that we discussed previously about the cells so they will create a poster.

Although we have made already a first approach to what a cell is, we will keep diving in its concept by reading Cells An Owner’s Handbook.34 It is a really fun and illustrative book for my students. It reveals what a cell is, how it splits and its different jobs in our body. They will read it using “Partner Reading” strategy so they can support each other to get a deep comprehension while they read in partners. After reading, they will reflect on three questions, discuss their answers and write them down in their notebooks using “Think-Pair-Share” strategy. These questions are: What is a cell? Could you give some examples of different cell jobs? Why does a cell split in two and so on?

To include something more manipulative, we will dedicate time with the school’s microscopes, so we will observe the skin cell of an onion. I will demonstrate how to separate the fleshy layers of the onion and peel off the thin skin in between. This skin is made up of a single layer of cells, which allows easy visualization of cells in the microscope. The students will take notes about their observations to share them with the whole group. After that, they will compare the onion’s cell with human hair. So, I will ask my students to pluck a hair from their heads and place it under the cover slip on their microscope slide, next to an onion cell. Then, we will comment our observations, and they will have the chance to explore more body cells through the virtual microscope in a website named “OpenSciEd Virtual Microscope.”35

After my students’ observations and conclusions, they will create a cell model to represent what they saw when they observed onion skin cells under the microscope. To build it, we will need one small and one large resealable plastic bag, and a twelve-foot length of yarn. They should be able to create a simple cell model by placing the yarn inside the small bag and then placing this inside the larger bag. I will remind them that groups of similar cells combine with each other to form tissues. For example, the layer of onion skin that they observed under the microscope is a tissue. I will split the class into two groups, and I will challenge each team to recreate what they saw when they looked at the sheet of onion skin, using their cell models and tape. The students should figure out that they can use the tape to join all their cells together to create one big sheet of onion skin (a tissue). Then, I will ask them “So, how are our organs formed?” To answer this question, my students will watch some videos like “Organization of Living Beings.”36 I will give them some minutes to put in practice the “Think, pair and share” strategy. Then, I will invite them to put together their tissues, so they will realize and visualize that different tissues organized together form an organ. Each organ of our body is made like that.

The previous activity will lead us to understand how we become an embryo and a complete body from a cell. First, the whole group will see this 3D animation37 of how a cell splits and develops until an embryo and a fetus are formed. Then, they will watch the video “Pregnancy: A Month-By-Month Guide”38 and, in groups of four, will draw the process of growing inside of the mother’s womb on a poster. The students may search for some other videos or rewatch the video to be able to explain how the body is formed.

Creating a Science TV Show

To wrap up the unit, my students will divide into groups and will conduct a TV show about this science unit. They will think and put a name on their TV show. After that, they will choose one of the three blocks of content (genetic material, how we differ from chimpanzees and from a cell to a complete body) and will become experts of the information they chose to play out on the TV show what will require to conduct research. They will talk about that subject, giving some examples. For that, they will be able to create materials like images, posters or slides to use during the show. Once their videos are recorded, we will share these videos with other grades, especially with 3rd and 5th grade, to be displayed in their classes.

Assessment Using Rubrics

To finish with the unit, I consider the assessment very important not only to evaluate my students but also to let students assess themselves and between them. To carry out the evaluation process, we will use “Rubrics” at the end of each week of block of contents. Rubrics are an extremely useful and effective tool for both teachers and students. As a teacher, this tool will help me to assign more objective and realistic grades. For the students using the rubric to assess themselves, it will allow them to reflect not only on their learning process but also on their final products. Also, my students will be able to assess their classmates after the final product, the TV show. The rubric will have clear standards set up and scores from 1 to 4, being 1 “Needs improvement” and 4 “Excellent”.

Resources

  • Chin, Jason. The Universe in You: A Microscopic Journey. First edition., Neal Porter Books/Holiday House, 2022.

I will use this book to introduce the unit because it tells in an engaging way the intricate structures of the cells, molecules, and atoms that make up every human body.

  • Quealy-Gainer, Kate. “We Go Way Back by Idan Ben-Barak.” Bulletin of the Center for Children’s Books, vol. 76, no. 5, Jan. 2023, pp. 149–149. DOI.org (Crossref), https://doi.org/10.1353/bcc.2023.0006.

This book illustrates very easily how it all began, especially how humans as a single cell became a structured body.

  • Fisher, Carolyn. Cells: An Owner’s Handbook. First edition., Beach Lane Books, 2019.

We will read this book to understand better cells and their functions in our body.

This website will be used by students to read some articles and watch videos. Also, it will be useful to search for information.

This website shows some nice pictures and videos about chimpanzees. Also, they can dig into some articles which talk about how different we are from the chimps.

  • The Human Sparks on PBS (Public Broadcasting Service).

A show that is available to stream on pbs.org about science. I will use it to watch a video that compares chimpanzees and human skills.

Appendix

These are the Oklahoma Academic Standards for Science and Language Arts that we must acquire at the end of the unit.

Science

4.LS1.1 Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.

We will dig into our internal structures such as the organs and how they formed from a single cell. Then, we will learn about external structures by analyzing our traits (why we look like that) besides comparing our behavior with chimpanzees.

4.LS1.2 Use a model to describe that animals receive different types of information through their senses, process the information in their brain, and respond to the information in different ways.

My students will analyze how different chimpanzees think and process information from humans by watching some videos and reading articles.

ELA (English Language Arts)

4.6.R.1 Students will conduct research to answer questions, including self-generated questions, and to build knowledge, using multiple sources (e.g., visual and text reference sources, electronic resources, and/or interviews).

Watching videos, researching and reading will be the main activities. My students will have to read texts, watch videos on the Internet and analyze them to answer questions as well as generating them for other students.

4.7.W ​Students will communicate their ideas, thoughts, and feelings by combining two or more kinds of content:

  • writing/alphabetic
  • sound, visual, and/or spatial
  • movement

We will use multimodal literacies to comprehend and communicate ideas, thoughts and information. For instance, my students will explore books, articles, videos, images, posters and/or charts. Also, they will create multimodal content to express their learning when they present their science TV show because they must use their voice but also some sources that they have previously created such as posters, images even presentation slides.

Bibliography

Books

Carroll, Sean B. Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom. 1. ed., Norton, 2005.

Cooper, Geoffrey M., and Robert E. Hausman. The Cell: A Molecular Approach. 4th ed, ASM Press ; Sinauer Associates, 2007.

Chin, Jason. The Universe in You: A Microscopic Journey. First edition., Neal Porter Books/Holiday House, 2022.

Duve, Christian de. Blueprint for a Cell: The Nature and Origin of Life. N. Patterson, 1991.

Darnell, James E., Harvey F. Lodish, and David Baltimore. Molecular Cell Biology. 2nd ed. New York: Scientific American Books : Distributed by W.H. Freeman, 1990.

Fields, Stanley, and Mark Johnston. Genetic Twists of Fate. The MIT Press, 2010.

Fisher, Carolyn. Cells: An Owner’s Handbook. First edition., Beach Lane Books, 2019.

Karp, Gerald. Cell and Molecular Biology: Concepts and Experiments. 6th ed., John Wiley, 2010.

Larsen, Clark Spencer. Our Origins: Discovering Biological Anthropology. Fifth Edition, W.W. Norton & Company, 2019.

Macaulay, David, and Richard Walker. The Way We Work : Getting to Know the Amazing Human Body. Boston: Houghton Mifflin, 2008.

Martinez Arias, Alfonso. The Master Builder: How the New Science of the Cell Is Rewriting the Story of Life. First edition., Basic Books, 2023.

Mukherjee, Siddhartha. Song of the Cell: An Exploration of Medicine and the New Human. Scribner, 2023.

Quealy-Gainer, Kate. “We Go Way Back by Idan Ben-Barak.” Bulletin of the Center for Children’s Books, vol. 76, no. 5, Jan. 2023, pp. 149–149. DOI.org (Crossref), https://doi.org/10.1353/bcc.2023.0006.

Richards, Julia E., and R. Scott Hawley. The Human Genome: A User’s Guide. 3rd ed. Amsterdam: Elsevier Academic Press, 2011.

Stanger, Ben. From One Cell: A Journey into Life’s Origins and the Future of Medicine. W.W. Norton & Company, 2023.

Articles

Weiss, K.M. The Intelligent Egg, and How It Got That Way: from Genes to Genius in a Few Easy Lessons. Evo Edu Outreach 5, 194–202 (2012). https://doi.org/10.1007/s12052-012-0412-3. Accessed February 1st, 2025.

Minter, Melissa, et al. “What Is Genetic Diversity and Why Does It Matter?” Frontiers for Young Minds, vol. 9, Dec. 2021, p. 656168. DOI.org (Crossref). Accessed February 15th, 2025. https://doi.org/10.3389/frym.2021.656168.

Khan Academy. https://www.khanacademy.org/partner-content/amnh/human-evolutio/human-evolution-the-evidence/a/understanding-our-past-dna. Accessed February 15th, 2025.

“What Is Epigenetics?” Cleveland Clinic. Accessed February 22nd, 2025.

https://my.clevelandclinic.org/health/articles/epigenetics.

Websites

Accumulating Glitches | Exploring the Grandeur of evolution | Epigenetics and Evolution. Accessed January 14th, 2025.

https://www.nature.com/scitable/blog/accumulating-glitches/epigenetics_and_evolution

Sciencing |Eukaryotic Cell: Definition, Structure & Function (With Analogy & Diagram): Aug 30, 2022 by Sylvie Tremblay. Accessed December 11th, 2024.

https://www.sciencing.com/eukaryotic-cell-definition-structure-function-with-analogy-diagram-13717298

LibreTexts Biology | 2.3: Eukaryotic Cell: Structure and Function. Accessed December 11th, 2024.

https://bio.libretexts.org/Courses/University_of_California_Davis/BIS_2A%3A_Introductory_Biology_(Easlon)/Readings/02.3%3A_Eukaryotic_Cell%3A_Structure_and_Function

ScienceFacts.net | Eukaryotic Cell: Definition, Structure, & Examples. Accessed December 11th, 2024.

Eukaryotic Cell

National Institutes of Health. Accessed January 17th, 2025, https://commonfund.nih.gov/HuBMAP

It shows an interesting project to describe all the cells in the human body, https://www.nature.com/scitable/topicpage/cell-energy-and-cell-functions-14024533

National Library of Medicine | The origin and evolution of cells, https://www.ncbi.nlm.nih.gov/books/NBK9841

Berkeley. University of California | Understanding Evolution. Accessed January 25th, 2025, https://evolution.berkeley.edu

American Museum of National History | DNA: Comparing Humans and Chimps. Accessed February 1st, 2025, https://www.amnh.org/exhibitions/permanent/human-origins/understanding-our-past/dna-comparing-humans-and-chimps

Columbia Daily Tribune | Untangled: The story of human hair. Accessed February 15th, 2025, https://www.columbiatribune.com/story/lifestyle/family/2015/02/18/untangled-story-human-hair/21748265007

Discover Magazine | How Does a Single Cell Become a Whole Body? Accessed December 11th, 2024, https://www.discovermagazine.com/mind/how-does-a-single-cell-become-a-whole-body

Prodigy | 8 Active Learning Strategies and Examples. Accessed January 8th, 2025, https://www.prodigygame.com/main-en/blog/active-learning-strategies-examples

“The very first living thing.” YouTube. Accessed December 11th, 2024.

“Evolutionary History: The Timeline of Life.” YouTube, Accessed December 11th, 2024.

“The RNA origin of life.” YouTube, Accessed January 8th, 2025.

“Epigenetics.” YouTube, Accessed February 15th, 2025.

“Gene Expression and Regulation”. YouTube, Accessed February 28th, 2025.

“Human Evolution: We Didn’t Evolve From Chimps.” YouTube, Accessed February 1st, 2025.

PBS Learning Media |The Human Spark | Humans vs. Chimps. Accessed January 25th, 2025.

https://oeta.pbslearningmedia.org/resource/hs11.global.ancient.earl.humanvs/the-human-spark-humans-vs-chimps/?student=true&focus=true

“How Humans Are Almost Identical to Chimps, According to DNA.” YouTube, Accessed February 1st, 2025.

OpenSciEd Virtual Microscope. Accessed February 15th, 2025.

https://openscied-static.s3.amazonaws.com/HTML+Files/6.6+Cells+Virtual+Microscope+Final/index.html?version=lesson6

“Organization of Living Beings.” YouTube, Accessed December 11th, 2024.

“Human Embryonic Development | HHMI BioInteractive Video.” YouTube, Accessed December 1st, 2024.

“Pregnancy: A Month-By-Month Guide | 3D Animation.” YouTube, Accessed December 1st, 2024.

Notes

  1. Larsen, Clark Spencer. Our Origins: Discovering Biological Anthropology. Fifth Edition, W.W. Norton & Company, 2019. 56-59
  2. Larsen, C. 60.
  3. Larsen, C. 66-67.
  4. “What Is Epigenetics?” Cleveland Clinic. Accessed February 22nd, 2025. https://my.clevelandclinic.org/health/articles/epigenetics.
  5. Fields, Stanley, and Mark Johnston. Genetic Twists of Fate. The MIT Press, 2010. 38.
  6. Epigenetics and Evolution | Accumulating Glitches | Learn Science at Scitable. https://www.nature.com/scitable/blog/accumulating-glitches/epigenetics_and_evolution/. Accessed January 14th, 2025
  7. Epigenetics and Evolution | Accumulating Glitches | Learn Science at Scitable. https://www.nature.com/scitable/blog/accumulating-glitches/epigenetics_and_evolution/. Accessed January 14th, 2025.
  8. Mukherjee, Siddhartha. Song of the Cell: An Exploration of Medicine and the New Human. Scribner, 2023. 12.
  9. Berkeley. University of California | Understanding Evolution. Accessed January 25th, 2025, https://evolution.berkeley.edu
  10. Berkeley. University of California | Understanding Evolution. Accessed January 25th, 2025, https://evolution.berkeley.edu
  11. Berkeley. University of California | Understanding Evolution. Accessed January 25th, 2025, https://evolution.berkeley.edu
  12. American Museum of National History | DNA: Comparing Humans and Chimps. Accessed February 1st, 2025, https://www.amnh.org/exhibitions/permanent/human-origins/understanding-our-past/dna-comparing-humans-and-chimps
  13. Epigenetics and Evolution | Accumulating Glitches | Learn Science at Scitable. https://www.nature.com/scitable/blog/accumulating-glitches/epigenetics_and_evolution/. Accessed January 14th, 2025.
  14. American Museum of National History | DNA: Comparing Humans and Chimps. Accessed February 1st, 2025, https://www.amnh.org/exhibitions/permanent/human-origins/understanding-our-past/dna-comparing-humans-and-chimps
  15. Columbia Daily Tribune | Untangled: The story of human hair. Accessed February 15th, 2025, https://www.columbiatribune.com/story/lifestyle/family/2015/02/18/untangled-story-human-hair/21748265007
  16. Martinez Arias, Alfonso. The Master Builder: How the New Science of the Cell Is Rewriting the Story of Life. First edition., Basic Books, 2023. 181.
  17. Carroll, Sean B. Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom. 1. ed., Norton, 2005. 5.
  18. Stanger, Ben. From One Cell: A Journey into Life’s Origins and the Future of Medicine. W.W. Norton & Company, 2023. 8.
  19. Weiss, K.M. The Intelligent Egg, and How It Got That Way: from Genes to Genius in a Few Easy Lessons. Evo Edu Outreach 5, 194–202 (2012). https://doi.org/10.1007/s12052-012-0412-3.
  20. Weiss, K. 3.
  21. Discover Magazine | How Does a Single Cell Become a Whole Body? Accessed December 11th, 2024, https://www.discovermagazine.com/mind/how-does-a-single-cell-become-a-whole-body
  22. Fields, S. 42.
  23. The very first living thing. Accessed December 11th, 2024.
  24. Evolutionary History: The Timeline of Life. Accessed December 11th, 2024.
  25. The RNA origin of life. Accessed January 8th, 2025
  26. Minter, Melissa, et al. “What Is Genetic Diversity and Why Does It Matter?” Frontiers for Young Minds, vol. 9, Dec. 2021, p. 656168. DOI.org (Crossref). Accessed February 15th, 2025. https://doi.org/10.3389/frym.2021.656168.
  27. Epigenetics. Accessed February 15th, 2025.
  28. “Gene Expression and Regulation”. Accessed February 28th, 2025.
  29. Human Evolution: We Didn’t Evolve From Chimps. Accessed February 1st, 2025.
  30. PBS Learning Media |The Human Spark | Humans vs. Chimps. Accessed January 25th, 2025, https://oeta.pbslearningmedia.org/resource/hs11.global.ancient.earl.humanvs/the-human-spark-humans-vs-chimps/?student=true&focus=true
  31. Khan Academy. https://www.khanacademy.org/partner-content/amnh/human-evolutio/human-evolution-the-evidence/a/understanding-our-past-dna. Accessed February 15th, 2025.
  32. How Humans Are Almost Identical to Chimps, According to DNA. Accessed February 1st, 2025.
  33. Quealy-Gainer, Kate. “We Go Way Back by Idan Ben-Barak.” Bulletin of the Center for Children’s Books, vol. 76, no. 5, Jan. 2023, pp. 149–149. DOI.org (Crossref), https://doi.org/10.1353/bcc.2023.0006.
  34. Fisher, Carolyn. Cells: An Owner’s Handbook. First edition., Beach Lane Books, 2019.
  35. OpenSciEd Virtual Microscope. Accessed February 15th, 2025, https://openscied-static.s3.amazonaws.com/HTML+Files/6.6+Cells+Virtual+Microscope+Final/index.html?version=lesson6
  36. Organization of Living Beings. Accessed December 11th, 2024.
  37. Human Embryonic Development | HHMI BioInteractive Video. Accessed December 1st, 2024.
  38. Pregnancy: A Month-By-Month Guide | 3D Animation. Accessed December 1st, 2024.